1. Field of the Invention
The invention relates to a control device for an alternator mounted in a vehicle like an automobile, and in particular to an alternator control device that allows necessary checks and tests to be easily performed in a plant or the like.
2. Description of the Related Art
An alternator mounted in a vehicle is often commercially manufactured as an alternator assembly that incorporates a rectifier that rectifies alternating current output of the alternator, and an alternator control device. In some cases, the alternator control device incorporated in the alternator assembly includes many terminals such as: a power supply terminal B connected to an output terminal of the rectifier that rectifies phase voltage of the alternator; an earth terminal E that has the same electric potential as the body of the vehicle; and a field terminal f connected to a field coil of the alternator. Other terminals include: a phase voltage input terminal p to which the phase voltage of the alternator is input; an ignition terminal IG that is connected to a contact that is opened and closed by an ignition switch; a communication terminal FR that transmits information about the power generation state of the alternator to an external device like an engine control unit (hereinafter referred to as “ECU”); and a communication terminal C that receives a power generation control signal from the external device like the ECU.
Furthermore, alternator control devices have been proposed in the known art in which a single signal line carries two-way communication of, for example, an IG signal that is a power turn-on signal, an FR signal that is a power generation state signal, and a C signal that is a power generation control signal. Such alternator control devices aim to reduce the number of terminals and wires used (for example, refer to Patent Document JP-A-10-51976).
Normally, an alternator control device is provided with an overvoltage warning portion. If the generated voltage of the alternator becomes an overvoltage, and this overvoltage continues for a predetermined period or longer, the overvoltage warning portion generates an overvoltage warning. In addition, the alternator control device is provided with a load response function that, in the case that the power generation amount of the alternator is increased, increases the power generation amount gradually rather than increasing it suddenly. Adoption of this structure promotes improvement of the engine startability and improvement of the stability of engine idle control.
When the known alternator control devices are used to check the alternator's full power generation at the plant or the like, or when a check is conducted with an excitation switch connected to a field coil turned fully on such that the control device places the alternator in a state in which full power can be obtained, it takes a period of time for the load response function included in the alternator control device to complete load response control. As a result, it is necessary to wait a few tens of seconds until full power is attained after the excitation switch is fully turned on. Accordingly, it takes a period of time to complete the check.